In recent years, investigation has been made toward commercialization and distribution of a safe driving support wireless system using an intelligent transport system (ITS). In the safe driving support wireless system, it is necessary to attract attention of a driver of a vehicle to avoid an accident by communicating location information or the like of the vehicle by inter-vehicle communication in which vehicle-mounted terminal devices mounted on the vehicle communicate with each other, or by road-to-vehicle communication for communication between a road-side device installed on a roadway and a vehicle-mounted terminal device.
In recent years, in order to prevent a pedestrian accident, a pedestrian-vehicle communication for communication between a pedestrian terminal device carried by a pedestrian and a vehicle-mounted terminal device has been proposed. In the pedestrian-vehicle communication, the pedestrian terminal device and the vehicle-mounted terminal device communicate with each other directly so that it is possible to attract attention of both of the pedestrian and the driver of the vehicle at an appropriate timing, and thus, great effect is expected in preventing pedestrian accidents.
Now, in a situation in which there are many pedestrians and vehicles similar to intersections of downtown areas and roadways around event sites, such as fireworks festivals, as the number of pedestrian terminal devices and vehicle-mounted terminal devices increases, the traffic of pedestrian-vehicle communication increases, and there is a concern that congestion of pedestrian-vehicle communication occurs. Therefore, it is desirable to reduce the frequency of pedestrian-vehicle communication, and to reduce the traffic of pedestrian-vehicle communication. In particular, since the number of pedestrians is often greater than the number of vehicles, reducing the frequency of pedestrian-vehicle communication in the pedestrian terminal device is effective in reducing the traffic of pedestrian-vehicle communication.
As a technology related to reducing the frequency of pedestrian-vehicle communication in such a pedestrian terminal device, in the related art, based on the location, moving speed, traveling direction, and the like of a pedestrian and a vehicle, by acquiring the risk of collision of a vehicle with a pedestrian, the communication control is performed in accordance with the risk, and in particular, in the pedestrian terminal device having a low risk, a technology of stopping the transmission of pedestrian information is known (refer to PTL 1). In addition, a technology in which the risk of collision of a vehicle with a pedestrian is acquired, the pedestrian terminal device having a high risk becomes a delegate terminal, the pedestrian terminal device having a low risk exchanges information with a vehicle-mounted terminal device via the pedestrian terminal device which is the delegate terminal, is known (refer to PTL 2).